Browsing by Author "Figueiredo, Ana R."
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- Ability of lactic acid bacteria to produce volatile phenolsPublication . Couto, José A.; Campos, Francisco M.; Figueiredo, Ana R.; Hogg, Tim A.Thirty-live strains of lactic acid bacteria (20 species) were screened for the ability to produce volatile phenols from the corresponding phenolic acids, p-coumaric and ferulic, in culture medium. The concentration of vinylphertols and ethylphenols in the growth mediuro was analyzed by gas chromatography. Results showed that 13 strains t3?%) were able to produce volatile phenols from p-coumaric acid, although only three (9%) produced 4-ethylphcnnl. the final product of the p-coumnric acid metabolic pathway. The reduction step of this pathway was only l`ound in the Lactobacillus genus: L brevis, L. cotlinoider, and L plnntnrttrrt. Seven of the eight pediococci strains studied were able to produce 4-vinylphenol but not 6-ethylphenol from p-coumaric acid. The two Oenococcus nent strains und the strain of Leuconostoc rneseitterriirler studied did ROI produce either of the two p-coumaric acid derivatives. Strains that produced volatile phenols were used in subsequent studies at lower phenolic acid con-centrations. Experiments with added 5 mgfL oi`p-cottniaric acid showed that some strains can still produce re1atively high (up to S00 ugiL) concentrations of 4-ethylphenol. The capacity of lactic acid bacteria to produce volatile phenols from l`crulic acid was much lower than its capacity to produce volatile phcrtols from pecouniaric acid.
- Cell membrane damage induced by phenolic acids on wine lactic acid bacteriaPublication . Campos, Francisco M.; Couto, José A.; Figueiredo, Ana R.; Tóth, Ildikó V.; Rangel, António O. S. S.; Hogg, Tim
- Effect of phenolic acids on glucose and organic acid metabolism by lactic acid bacteria from winePublication . Campos, Francisco M.; Figueiredo, Ana R.; Hogg, Tim; Couto, José A.The influence of phenolic (p-coumaric, caffeic, ferulic, gallic and protocatechuic) acids on glucose and organic acid metabolism by two strains of wine lactic acid bacteria (Oenococcus oeni VF and Lactobacillus hilgardii 5) was investigated. Cultures were grown in modified MRS medium supplemented with different phenolic acids. Cellular growth was monitored and metabolite concentrations were determined by HPLC-RI. Despite the strong inhibitory effect of most tested phenolic acids on the growth of O. oeni VF, the malolactic activity of this strain was not considerably affected by these compounds. While less affected in its growth, the capacity of L. hilgardii 5 to degrade malic acid was clearly diminished. Except for gallic acid, the addition of phenolic acids delayed the metabolism of glucose and citric acid in both strains tested. It was also found that the presence of hydroxycinnamic acids (p-coumaric, caffeic and ferulic) increased the yield of lactic and acetic acid production from glucose by O. oeni VF and not by L. hilgardii 5. The results show that important oenological characteristics of wine lactic acid bacteria, such as the malolactic activity and the production of volatile organic acids, may be differently affected by the presence of phenolic acids, depending on the bacterial species or strain.
- Fluorimetric detection of cell membrane lesions in wine lactic acid bacteria exposed to phenolic compoundsPublication . Moreira, Joana; Reis, Olga; Campos, Francisco M.; Tóth, Ildikó V.; Figueiredo, Ana R.; Couto, José A.; Rangel, António O. S. S.; Hogg, Tim
- Influence of phenolic compounds on glucose and organic acids metabolism of wine lactic acid bacteriaPublication . Bilé, Teresa; Sá, Filipa; Campos, Francisco M.; Figueiredo, Ana R.; Couto, José A.; Hogg, Tim
- Production of volatile phenols by lactic acid bacteriaPublication . Couto, José A.; Campos, Francisco M.; Figueiredo, Ana R.; Hogg, Tim
- Production of volatile phenols by wine PediococciPublication . Couto, José A.; Campos, Francisco M.; Figueiredo, Ana R.; Hogg, Tim